this be probably the best atomic projection clock if all you want be a time display function . I have several of of this model . it have a bright-enough projection display , can do 24-hour format -lrb- unlike Oregon Scientific model -rrb- , relatively easy to setup -lrb- for a atomic clock -rrb- , and the most affordable . as be with most digital clock , set up the alarm be a hassle and I do not use it . negative # 1 : the power-supply be only for the projection and all setting be lose when battery be change . the trick be to replace one battery at a time and quickly to retain the setting . negative # 2 : when place behind you , say on a bed headboard , the display can not be rotate enough for proper orientation while sleep . there be a plastic tab inside the projector that can be force break to override it .